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1e62865cf9
This commit adds a tutorial on fuzzing with the go-fuzz library into the docs folder. It includes an introduction to fuzzing, setup and installation steps to run go-fuzz with lnd, tips to generate a valid corpus for use with go-fuzz, and finally it includes a small explanation of the test harness that was used to find bugs in lnd.
54 lines
1.6 KiB
Go
54 lines
1.6 KiB
Go
package wirefuzz
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import (
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"bytes"
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"fmt"
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"github.com/lightningnetwork/lnd/lnwire"
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"reflect"
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)
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// Fuzz is used by go-fuzz to fuzz for potentially malicious input
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func Fuzz(data []byte) int {
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// Because go-fuzz requires this function signature with a []byte parameter,
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// and we want to emulate the behavior of mainScenario in lnwire_test.go,
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// we first parse the []byte parameter into a Message type.
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// Parsing []byte into Message
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r := bytes.NewReader(data)
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msg, err := lnwire.ReadMessage(r, 0)
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if err != nil {
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// Ignore this input - go-fuzz generated []byte that cannot be represented as Message
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return 0
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}
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// We will serialize Message into a new bytes buffer
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var b bytes.Buffer
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if _, err := lnwire.WriteMessage(&b, msg, 0); err != nil {
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// Could not serialize Message into bytes buffer, panic
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panic(err)
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}
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// Make sure serialized bytes buffer (excluding 2 bytes for message type
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// is less than max payload size for this specific message,.
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payloadLen := uint32(b.Len()) - 2
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if payloadLen > msg.MaxPayloadLength(0) {
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// Ignore this input - max payload constraint violated
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return 0
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}
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// Deserialize the message from the serialized bytes buffer and
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// assert that the original message is equal to the newly deserialized message.
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newMsg, err := lnwire.ReadMessage(&b, 0)
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if err != nil {
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// Could not deserialize message from bytes buffer, panic
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panic(err)
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}
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if !reflect.DeepEqual(msg, newMsg) {
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// Deserialized message and original message are not deeply equal
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panic(fmt.Errorf("Deserialized message and original message " +
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"are not deeply equal."))
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}
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return 1
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}
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